This invention relates to an improved release device of the type which is explosively actuated. It has particular application as a release device for a call buoy but is also useful for the release of other devices, including release underground or in the air.
One of the objects of the invention is to provide a compact, reliable release device that is operated by an explosive cartridge. It is also important that the device have a large holding strength, that is, be able to resist in its unactuated state a considerable tensile load and that there be a large strength-to-weight ratio.
Some release devices are objectionable in that they tend to fragment when the explosive action occurs, and it is important in the present device that there be no serious danger of flying fragmentation, such as is generally associated with explosive bolts and similar devices that contain high explosives.
In devices of the type heretofore in use there have been difficulties in transportation and other objections due to the use of high explosives. The present device is designed to be operated without some of these high explosives to provide a reliable release device in which there are two separable components and no creation of other loose parts, fragments, contaminants, or of objectionable gases.
As indicated above, one particular use of the present invention is in conjunction with an underwater call buoy, that is, a portable, self-contained assembly consisting of an electronic module, a battery pack, a buoy housing, an explosive release device, a steel cable and a buoy nest. All the devices except the explosive release device are in themselves old. The buoy housing is attached to the buoy nest by the explosive release device, and, in use, the call buoy is installed on the ocean floor at a site that is to be relocated from the ocean surface at a later date. At the time of recall, a command module on board a surface vessel transmits a coded acoustic (or other) signal that is picked up by the call buoy's electronic module. At that time, then, the electronic module applies an electrical pulse to the bridge wire of the explosive cartridge through underwater electrical lead wires and connections that form part of the explosive release device.
When the explosive cartridge is fired, a high pressure gas is generated that is used in the present invention to shear off a retaining flange on a retaining bolt and to force a retaining block up in such a way as to release a clevis forming part of the explosive release device from a tongue end forming another part thereof. The explosive release then enables the clevis and tongue to separate, so that the call buoy can float to the surface, trailing a steel cable which is attached to the buoy nest and which anchors the call buoy to the ocean floor. This cable may be used to provide a guide line enabling divers to swim to the site of the buoy nest.
Whether used in connection with a call buoy or with some other device requiring a similar release, the present invention is particularly designed to avoid fragmentation, loose parts, contaminants, or gases.
It is an object of the invention to cause the explosively-actuated cartridge to remain with one part of the device (e.g., to remain with the call buoy and float to the top with it), and to resist while it is on its site (e.g., the ocean floor) rather considerable tensile forces exerted (e.g., by the call buoy tending to cause it to rise to the surface). It is also important that the device be completely reliable so that when the charge is exploded the device actuates promptly and accurately.
Furthermore, one object of the invention is to provide a structure such that relatively insensitive explosives like those used in rifle bullets can be used instead of high explosives, which product fragments, as has been the case heretofore. As a result, no special care need be taken in shipping and handling devices of this invention, unlike the care of the hazardous prior-art devices.
Also, an object of the invention is to provide a release device that will mate with ordinary chain shackles and eye bolts and can be installed quickly.